'\" te
.\" Copyright (c) 2004, Sun Microsystems, Inc., All Rights Reserved
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
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.TH USB_PIPE_ISOC_XFER 9F "Sep 16, 2016"
.SH NAME
usb_pipe_isoc_xfer, usb_pipe_stop_isoc_polling \- USB isochronous transfer and
polling functions
.SH SYNOPSIS
.nf
#include <sys/usb/usba.h>



\fBint \fR\fBusb_pipe_isoc_xfer\fR(\fBusb_pipe_handle_t\fR \fIpipe_handle\fR, \fBusb_isoc_req_t *\fR\fIrequest\fR,
     \fBusb_flags_t\fR \fIflags\fR);
.fi

.LP
.nf
\fB\fR

\fBvoid \fR\fBusb_pipe_stop_isoc_polling\fR(\fBusb_pipe_handle_t\fR \fIpipe_handle\fR, \fBusb__flags_t\fR \fIflags\fR);
.fi

.SH INTERFACE LEVEL
illumos DDI specific (illumos DDI)
.SH PARAMETERS
For \fBusb_pipe_isoc_xfer()\fR:
.sp
.ne 2
.na
\fB\fIpipe_handle\fR\fR
.ad
.RS 15n
Isochronous pipe handle on which request is made.
.RE

.sp
.ne 2
.na
\fB\fIrequest\fR\fR
.ad
.RS 15n
Pointer to isochronous transfer request.
.RE

.sp
.ne 2
.na
\fB\fIflags\fR\fR
.ad
.RS 15n
USB_FLAGS_SLEEP is the only flag recognized. Wait for needed resources if
unavailable.
.RE

.sp
.LP
For \fBusb_pipe_stop_isoc_polling()\fR:
.sp
.ne 2
.na
\fB\fIpipe_handle\fR\fR
.ad
.RS 15n
Isochronous pipe handle on which to stop polling for input.
.RE

.sp
.ne 2
.na
\fB\fIflags\fR\fR
.ad
.RS 15n
USB_FLAGS_SLEEP is the only flag recognized. Wait for polling to stop.
.RE

.SH DESCRIPTION
The \fBusb_pipe_isoc_xfer()\fR function requests the USBA framework to perform
a transfer     through a USB isochronous pipe. The request is passed to the
host controller driver (HCD), which performs the necessary transactions to
complete the request.
.sp
.LP
By their nature, isochronous transfers require several transactions for
completion. Each request may contain several packet descriptors. Descriptors
correspond to subtransfers to be made in different frames. A request is deemed
completed once all packets of that request have been processed.  It is illegal
to specify the USB_ATTRS_ONE_XFER attribute in an isochronous request.  The
isochronous polling interval is always one millisecond, the period of a
full-speed frame.
.sp
.LP
All isochronous requests are asynchronous, and will notify the caller of
their completion via a callback function.  All isochronous requests must
specify normal and exception callback handlers.
.sp
.LP
Requests will wait for needed, unavailable resources when USB_FLAGS_SLEEP has
been specified in flags.  Requests made without USB_FLAGS_SLEEP set will fail
if needed resources are not readily available.
.sp
.LP
No errors seen during request processing will result in aborted transfers or
exception callbacks. Such errors will instead be logged in the packet
descriptor's isoc_pkt_status field. These errors can be examined when the
completed request is returned through a normal callback.
.SS "Isochronous-OUT TRANSFERS"
Allocate room for data when allocating isochronous-OUT requests via
usb_alloc_isoc_req(9F), by passing a positive value for     the \fIlen\fR
argument. The data will be divided among the request transactions, each
transaction represented by a packet descriptor.  (See usb_isoc_request(9S).
When all of the data has been sent, regardless of any errors encountered, a
normal transfer callback will be     made to notify the client driver of
completion.
.sp
.LP
If a request is submitted while other requests are active or queued, and the
new request has its USB_ATTRS_ISOC_XFER_ASAP attribute set, the host controller
driver will queue the request to start on a frame which immediately follows the
last frame of the last queued request.
.SS "Isochronous-IN TRANSFERS"
All isochronous-IN transfers start background polling, and require only a
single (original) request.  The USBA framework will allocate a new request each
time polling has new data to return. Specify a zero length when calling
usb_alloc_isoc_req() to allocate the original request, since it will not be
used to return data.  Set the isoc_pkts_length in the request to specify how
much data to poll per interval (the length of one packet in the request).
.sp
.LP
The original request passed to \fBusb_pipe_isoc_xfer()\fR will be used to
return status when polling termination is requested, or for error condition
notification. There can be only one isochronous-IN request submitted at a time.
.SS "CALLBACKS"
Isochronous transfer normal-completion callbacks cannot block for any reason
since they are called from interrupt context.  They will have
USB_CB_INTR_CONTEXT set in their callback flags to note this.
.sp
.LP
Isochronous exception callbacks have the following restrictions for blocking:
.RS +4
.TP
1.
They can block for resources (for example to allocate memory).
.RE
.RS +4
.TP
2.
They cannot block for synchronous completion of a command (for example
usb_pipe_close(9F)) done on the same pipe.  Asynchronous commands can be
started, when the pipe's policy pp_max_async_reqs field is initialized to
accommodate them.
.RE
.RS +4
.TP
3.
They cannot block waiting for another callback to complete.
.RE
.RS +4
.TP
4.
 They cannot block waiting for a synchronous transfer request to complete.
They can, however, make an asynchronous request (such as restarting polling
with a new isochronous-IN transfer).
.RE
.sp
.LP
Please see the section on callbacks in \fBusb_callback_flags\fR(9S) for more
information.
.sp
.LP
All isochronous transfer exception callbacks signify that polling has stopped.
Polling requests are returned with the following completion reasons:
.sp
.in +2
.nf
        USB_CR_STOPPED_POLLING
        USB_CR_PIPE_CLOSING
.fi
.in -2

.sp
.LP
Note: There are no exception callbacks for error conditions.
.sp
.LP
The \fBusb_pipe_stop_isoc_polling()\fR function terminates polling on an
isochronous-IN pipe. The \fBusb_pipe_stop_isoc_polling()\fR function does the
following:
.RS +4
.TP
1.
Cease polling.
.RE
.RS +4
.TP
2.
Allow any requests-in-progress to complete and be returned to the client
driver through the normal callback mechanism.
.RE
.RS +4
.TP
3.
Idle the pipe.
.RE
.RS +4
.TP
4.
Return the original polling request to the client driver through an
exception callback with a completion reason of
USB_CR_STOPPED_POLLING.
.RE
.SH RETURN VALUES
For \fBusb_pipe_isoc_xfer()\fR:
.sp
.ne 2
.na
\fBUSB_SUCCESS\fR
.ad
.RS 27n
Transfer was successful.
.RE

.sp
.ne 2
.na
\fBUSB_INVALID_ARGS\fR
.ad
.RS 27n
Request is \fBNULL\fR.
.RE

.sp
.ne 2
.na
\fBUSB_INVALID_CONTEXT\fR
.ad
.RS 27n
Called from interrupt context with the USB_FLAGS_SLEEP flag set.
.RE

.sp
.ne 2
.na
\fBUSB_INVALID_REQUEST\fR
.ad
.RS 27n
The request has been freed or otherwise invalidated.
.sp
A set of conflicting  attributes were specified. See
\fBusb_isoc_request\fR(9S).
.sp
The normal   and/or exception callback was NULL, USB_FLAGS_SLEEP  was  not set
and USB_ATTRS_ONE_XFER was not set.
.sp
An isochronous request was specified with a zeroed isoc_pkt_descr, a NULL
isoc_pkt_descr, or a NULL data argument.
.sp
An isochronous request was specified with USB_ATTRS_ISOC_XFER_ASAP and a
nonzero isoc_frame_no.
.RE

.sp
.ne 2
.na
\fBUSB_NO_FRAME_NUMBER\fR
.ad
.RS 27n
An isochronous request was not specified with one and only one   of
USB_ATTRS_ISOC_START_FRAME or USB_ATTRS_ISOC_XFER_ASAP specified.
.sp
An  isochronous request was specified with USB_ATTRS_ISOC_START_FRAME and a
zero isoc_frame_no.
.RE

.sp
.ne 2
.na
\fBUSB_INVALID_START_FRAME\fR
.ad
.RS 27n
An isochronous request was specified with an invalid starting frame number
(less than current frame number, or zero) and USB_ATTRS_ISOC_START_FRAME
specified.
.RE

.sp
.ne 2
.na
\fBUSB_INVALID_PIPE\fR
.ad
.RS 27n
Pipe handle is NULL or invalid.
.sp
 Pipe is closing or closed.
.RE

.sp
.ne 2
.na
\fBUSB_PIPE_ERROR\fR
.ad
.RS 27n
Pipe  handle refers to a pipe which is in the USB_PIPE_STATE_ERROR state.
.RE

.sp
.ne 2
.na
\fBUSB_NO_RESOURCES\fR
.ad
.RS 27n
Memory, descriptors or other resources unavailable.
.RE

.sp
.ne 2
.na
\fBUSB_HC_HARDWARE_ERROR\fR
.ad
.RS 27n
Host controller is in error state.
.RE

.sp
.ne 2
.na
\fBUSB_FAILURE\fR
.ad
.RS 27n
An asynchronous transfer failed or an internal error occurred.
.sp
.in +2
.nf
An isoch request requested too much data:
    (length   >  (usb_get_max_pkts_per_isoc_request()  *
     endpoint's  wMaxPacketSize))
.fi
.in -2

The pipe is in an unsuitable state (error, busy, not ready).
.RE

.sp
.LP
Additional status information may be available in the isoc_completion_reason
and isoc_cb_flags fields of the request. Please see
\fBusb_completion_reason\fR(9S) and \fBusb_callback_flags\fR(9S) for more
information.
.sp
.LP
For \fBusb_pipe_stop_isoc_polling()\fR:
.sp
.LP
None, but will fail if called with USB_FLAGS_SLEEP specified from interrupt
context; the pipe handle is invalid, NULL or pertains to a closing or closed
pipe; or the pipe is in an error state. Messages regarding these errors will be
logged to the console logfile.
.SH CONTEXT
Both of these functions may be called from kernel or user context without
regard to arguments. May be called from interrupt context only when the
USB_FLAGS_SLEEP flag is clear.
.SH EXAMPLES
.in +2
.nf
/* Start polling on an isochronous-IN pipe. */

    usb_isoc_req_t isoc_req;
    void isoc_pipe_callback(usb_pipe_handle_t, usb_isoc_req_t*);
    void isoc_pipe_exception_callback(
        usb_pipe_handle_t, usb_isoc_req_t*);
    uint_t pkt_size;
    usb_ep_data_t *isoc_ep_tree_node;
    usb_ep_descr_t *isoc_ep_descr = ...;   /* From usb_lookup_ep_data() */

    isoc_ep_descr = &isoc_ep_tree_node->ep_descr;
    pkt_size = isoc_ep_descr->wMaxPacketSize;

    isoc_req = usb_alloc_isoc_req(
        dip, num_pkts, NUM_PKTS * pkt_size, USB_FLAGS_SLEEP);
    ...
    ...
    isoc_req->isoc_attributes = USB_ATTRS_ISOC_XFER_ASAP;
    ...
    ...
    isoc_req->isoc_cb         = isoc_pipe_callback;
    isoc_req->isoc_exc_cb     = isoc_pipe_exception_callback;
    ...
    ...
    isoc_req->isoc_pkts_length  = pkt_size;
    isoc_req->isoc_pkts_count   = NUM_PKTS;
    for (pkt = 0; pkt < NUM_PKTS; pkt++) {
            isoc_req->isoc_pkt_descr[pkt].isoc_pkt_length = pkt_size;
    }

    if ((rval = usb_pipe_isoc_xfer(pipe, isoc_req, USB_FLAGS_NOSLEEP))
        != USB_SUCCESS) {
            cmn_err (CE_WARN,"%s%d: Error starting isochronous pipe polling.",
                ddi_driver_name(dip), ddi_get_instance(dip));
    }

    -------

    /* Stop polling before powering off device. Wait for polling to stop. */

    usb_pipe_stop_isoc_polling(pipe, USB_FLAGS_SLEEP);
    pm_idle_component(dip, 0);

.fi
.in -2

.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Architecture	PCI-based systems
_
Interface stability	Evolving
.TE

.SH SEE ALSO
.BR attributes (7),
.BR usb_alloc_request (9F),
.BR usb_get_cfg (9F),
.BR usb_get_current_frame_number (9F),
.BR usb_get_max_pkts_per_isoc_request (9F),
.BR usb_get_status (9F),
.BR usb_pipe_bulk_xfer (9F),
.BR usb_pipe_ctrl_xfer (9F),
.BR usb_pipe_get_state (9F),
.BR usb_pipe_intr_xfer (9F),
.BR usb_pipe_reset (9F),
.BR usb_pipe_xopen (9F),
.BR usb_bulk_request (9S),
.BR usb_callback_flags (9S),
.BR usb_completion_reason (9S),
.BR usb_ctrl_request (9S),
.BR usb_ep_descr (9S),
.BR usb_intr_request (9S),
.BR usb_isoc_request (9S)
